Magnetic titrations are performed by determining the changing overall magnetic susceptibility of a liquid system when a reactant solution is added stepwise to that of another reactant. A magnetic titration apparatus and procedure have been developed which are based upon the Quincke method for measuring susceptibility. It is believed to have marked advantages over the Gouy technique. Magnetic titrations have been found to have great utility in the study of complexation reactions in solutions of several transition-metal ions. A practical apparatus and its use are described. Sources of error are analyzed, and sample titration curves are presented. Limitations of the method are discussed.